An apparatus, for instance a vending machine or a kitchen appliance, that is configured to prepare beverages, e.g. coffee, tea and/or chocolate milk, may typically include a dispenser that serves to dispense a predetermined dose of a loose product towards an area in which the beverages are prepared. The dispenser may comprise a hopper and an extruder. The loose product, e.g. coffee ground, tea ground or cacao powder, may be contained in the hopper at a bottom side of which the extruder may be arranged. The extruder may include a screw feeder comprising a helical blade that, when it is driven in rotation, feeds an amount of loose product from the hopper towards a product outlet or discharge opening, from which the loose product is dispensed to a unit for the preparation of the beverage.
A drawback of many conventional apparatus of the above-described type stems from the use of hot water to prepare the beverage. The hot water, which may take the form of water vapor or steam, may rise from the area where the beverage is prepared towards the discharge opening of the extruder. There, the moisture may be absorbed by the loose product and cause the product to lump together and degrade, as a result of which the extruder may start to malfunction (e.g. loose dosing accuracy or get stuck) and the beverages being prepared may diminish in quality.